> ## Documentation Index
> Fetch the complete documentation index at: https://www.plain.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# assignRolesToUser

> Assigns a role to a user in the workspace. Supply exactly one of `roleKey` (for built-in roles) or `customRoleId` (for custom roles) — not both. You can also set `usingBillingRotaSeat` to control whether the user occupies a billable seat on the billing rota. Requires the `roles:assign` permission.